How to look up a Contractors License,
by License number
by Business Name
by Personnel Name
or Salespersons name
https://www2.cslb.ca.gov/onlineservices/checklicenseII/checklicense.aspx
If they are licensed this is where you should find their Liability Insurance which is who you are a lawyer should contact for any damages they have caused to your property during the construction process.
CA STATE CONTRACTORS LICENSE BOARD - How to file a complaint
Create a notebook of dates/times.
Take pictures DOCUMENT, DOCUMENT, DOCUMENT.
https://www.cslb.ca.gov/Consumers/Filing_A_Complaint/
Once you file online you will be given a Case # and you will still have to submit in writing along with pictures of damage.
We realize YOU did not hire this company but this is one way to file a complaint.
There is another form on the California contractors website called a Lead Referral mostly for unlicensed contractors, working without permits and other violations.
https://www.cslb.ca.gov/OnlineServices/SWIFT/LeadReferral/Entry
We suggest filing with both.